to prevent Deep Vein Thrombosis (DVT) in Flight Clinically proven graduated compression system to improve circulation. Why You Should Wear Scholl Flight Socks: Long periods of inactivity, combined with the cramped conditions and dehydration which can occur on long journeys, can cause a number of circulatory problems including deep vein thrombosis (DVT)- blood clots. Scholl Flight Socks are medically proven to help prevent DVT by helping to improve blood flow. Designed for continuous comfort, they effectively help relieve tired aching legs and swollen ankles. Scholl Flight Socks are ultra soft, have a comfort top and look and feel like normal socks. Directions for Use: Scholl Flight Socks are designed to be worn in place of normal socks throughout your entire journey. Always wear both socks and ensure that they are pulled up to just below the knee. Please read information leaflet enclosed in packet. Warning: If you are suffering from, or have previous history of blood clots, a blood clotting disorder, heart or circulatory problems, diabetes, severe varicose veins, cancer, reduced mobility or if you have recently undergone major surgery or are pregnant, you should consult a healthcare professional about the suitability of this product. Calf Size 16" - 18" 40.5cms - 45cms Ankle Size 10 1/2" - 12 1/4" 26cms - 31cms